RU140685U1 - ENGINE SYSTEM - Google Patents

Abstract

A system for an engine, comprising: a positive crankcase ventilation system containing a crankcase ventilation tube, the crankcase ventilation tube being connected at the first end to the fresh air intake, and at the second end to the engine crankcase; a humidity sensor located inside the crankcase ventilation tube; absolute pressure sensor in the manifold; and a controller with machine-readable commands to adjust the engine operating parameters based on the moisture read by the moisture sensor and indicate degradation of the crankcase ventilation tube based on the moisture read by the moisture sensor and engine boost.

Description

FIELD OF TECHNOLOGY TO WHICH A USEFUL MODEL IS

This utility model relates to systems and methods for indicating that a crankcase ventilation pipe is disconnected from a crankcase ventilation system.

BACKGROUND

Engines may include crankcase ventilation systems for venting gases from the crankcase and into the engine inlet to provide continuous pumping of gases from the inside of the crankcase to reduce deterioration of various engine components in the crankcase. Under certain conditions, crankcase ventilation systems can be monitored to identify system integrity issues. For example, the crankcase ventilation pipe may become disconnected, and the oil filler cap may be removed or not tightened, the dipstick may not be positioned correctly, and / or other seals in the crankcase ventilation system may be impaired, resulting in poor performance of the various components included in the crankcase engine.

Various approaches can be used to monitor the integrity of the crankcase ventilation system. For example, a pressure sensor can be used in the crankcase, and a valve in the crankcase ventilation pipe can open so that changes in pressure or vacuum can be read in the crankcase to determine if there is a loss of integrity in the system.

In other approaches, a plurality of absolute value sensors, such as a barometric pressure sensor (BP), compressor inlet pressure sensor (CIP), throttle inlet pressure sensor (TIP), manifold air pressure sensor (MAP) and / or pressure sensor in the crankcase ventilation hose, etc., can be used in combination to control the integrity of the crankcase ventilation system (see, for example, US 2011197864, publ. 08/18/2011).

However, the authors in the materials of the present description revealed that such approaches can add additional hardware to such control systems, for example, additional sensors and valves, thereby increasing the cost and complexity of the crankcase ventilation control system. Additionally, some of these sensors may be of low utilization, for example, a pressure sensor in the crankcase can only be used to detect a violation of the integrity of the crankcase, thereby limiting the usefulness of such sensors.

ESSENCE OF A USEFUL MODEL

Thus, in one approach, in order to at least partially overcome these problems, a system for an engine is proposed comprising:

a forced crankcase ventilation system comprising a crankcase ventilation pipe, the crankcase ventilation pipe being connected at the first end to the fresh air inlet and at the second end to the engine crankcase;

humidity sensor located inside the crankcase ventilation tube;

manifold absolute pressure sensor;

and

a controller with machine-readable commands for adjusting engine operating parameters based on humidity read by a humidity sensor and indicating deterioration of the crankcase ventilation tube based on humidity read by a humidity sensor and engine boost

In addition, in one approach, a method for an engine is provided. The method includes a step at which deterioration of the crankcase ventilation tube based on humidity is indicated. Thus, the connection of the crankcase ventilation tube can be indicated by a humidity sensor, which is available to also provide information to other systems of the vehicle and / or engine.

In one example, humidity can be detected by a humidity sensor located in the crankcase ventilation pipe. Sensed humidity may vary depending on engine boost. For example, when the pressure in the intake manifold is less than the barometric pressure (naturally aspirated), the humidity sensor can read the ambient humidity. Environmental humidity information can then be used to adjust engine operating parameters. In yet another example, when the pressure in the intake manifold is greater than the barometric pressure (pressurized), the humidity sensor can read a humidity value greater than the ambient humidity when the crankcase ventilation pipe is connected. In some conditions, a humidity sensor may read a lower humidity value (for example, ambient humidity) when the crankcase ventilation pipe is disconnected. Thus, the deterioration of the crankcase ventilation tube can be diagnosed based on read humidity and engine boost.

In addition, the humidity sensor in the crankcase ventilation tube can be used to diagnose the functionality of the humidity sensor and determine an estimate of the rate of gas breakthrough. For example, if the reading of the humidity sensor does not change during the operation of the supercharged and naturally aspirated engine, the sensor may be subject to poor performance. In yet another example, a rise in humidity when the pressure in the intake manifold rises from below barometric pressure to above barometric pressure can approximate the rate of gas breakthrough. Essentially, a higher rate of increase in humidity and a higher rate of breakthrough of gases may indicate increased deterioration in engine performance.

Thus, a humidity sensor located in the crankcase ventilation tube can provide diagnostics of the engine's health. The humidity sensor can also provide environmental humidity data, under selected conditions, to control other engine systems, along with diagnosing the proper functioning of the humidity sensor. In conclusion, the humidity sensor may indicate that the crankcase ventilation pipe is disconnected.

It should be understood that the essence of the utility model presented above is presented to familiarize with the simplified form of the selection of concepts, which are additionally described in the detailed description. It is not intended to identify key or essential features of the claimed subject matter of a utility model, the scope of which is uniquely determined by the utility model formula that accompanies the detailed description. Moreover, the claimed subject matter of the utility model is not limited to the options for implementation, which exclude any disadvantages noted above or in any part of this description.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic illustration of an exemplary engine system including a forced crankcase ventilation system.

Figure 2 shows a flowchart of a method for diagnosing a crankcase ventilation pipe attachment.

Figure 3 shows a flowchart of a method for determining engine boost and gas breakthrough intensity.

4 shows a graphical example of a humidity sensor reading based on engine operating conditions.

DESCRIPTION OF PREFERRED EMBODIMENTS FOR USING THE USEFUL MODEL

The following description relates to systems and methods for indicating that a crankcase ventilation pipe is disconnected from a crankcase ventilation system, such as the system shown in FIG. The humidity sensor may be located in the crankcase ventilation tube to measure or evaluate humidity under different engine operating conditions. A method for diagnosing a crankcase ventilation pipe connection based on humidity is shown in FIG. Humidity sensor can read different values depending on engine boost. Humidity can also be used to determine the rate of gas breakthrough. Figure 3 represents a method for determining engine boost and gas breakthrough intensity. Exemplary humidity sensor readings based on engine operating conditions are shown in FIG. 4.

Further, with reference to FIG. 1, it shows an exemplary configuration of a multi-cylinder engine system, generally depicted under 10, which may be included in a vehicle power plant. The engine 10 may be controlled, at least in part, by a control system including a controller 48, and input signals from the vehicle driver 132 through the input device 130. In this example, the input device 130 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP.

The engine 10 may include a lower portion of the engine block, indicated generally at 26, which may include an engine crankcase 28 enclosing a crankshaft 30. The engine crankcase 28 includes gases and may include a crankcase 32. otherwise indicated by reference as an oil pan holding engine lubricant (eg, engine oil) located below the crankshaft. The oil filler neck 29 may be located on the crankcase 28 of the engine so that oil can be supplied to the pan 32 of the crankcase. The oil filler neck 29 may include an oil filler cap 33 to seal the oil filler neck 29 when the engine is in operation. The dipstick tube 37 may also be located in the crankcase 28 of the engine and may include an oil dipstick 35 for measuring the oil level in the oil pan 32. In addition, engine crankcase 28 may include many other service openings for components in engine crankcase 28. These openings in the crankcase 28 of the engine can be kept closed while the engine is running, so that the crankcase ventilation system (described below) can work when the engine is running.

The upper portion of the engine cylinder block 26 may include a combustion chamber 34 (i.e., a cylinder). The combustion chamber 34 may include walls 36 of the combustion chamber with a piston 38 located therein. The piston 38 may be attached to the crankshaft 30 so that the reciprocating motion of the piston is converted into rotational motion of the crankshaft. The combustion chamber 34 may receive fuel from fuel nozzles (not shown) and intake air from the intake manifold 42, which is located downstream of the throttle 44. The engine cylinder block 26 may also include an engine coolant temperature (ECT) sensor 46 located on the entrance to the controller 48 of the engine (described in more detail below in the materials of the present description).

The throttle 44 may be located at the inlet of the engine to control the air flow entering the intake manifold 42, and, for example, may be preceded by an upstream compressor 50 followed by a charge air cooler 52. The air filter 54 may be located upstream of the compressor 50 and may filter fresh air entering the inlet 56.

Exhaust gaseous products of combustion exit the combustion chamber 34 through an exhaust channel 60 located upstream of the turbine 62. Exhaust gas sensor 64 may be located along the exhaust channel 60 upstream of the turbine 62. The turbine 62 may be equipped with a boost pressure regulator bypassing her. Sensor 64 may be a sensor suitable for measuring the fuel-air ratio of exhaust gases, such as a linear oxygen sensor or UEGO (universal or wide-range oxygen sensor for exhaust gases), a dual-mode oxygen sensor or EGO, HEGO (heated EGO), NOx sensor , HC, or CO. An exhaust sensor 64 may be coupled to a controller 48.

In the example of FIG. 1, a crankcase ventilation (PCV) system 16 is connected to the engine inlet, so that gases in the crankcase can be ventilated in a controlled manner from the crankcase. In naturally aspirated conditions (when the pressure in the intake manifold (MAP) is less than the barometric pressure (BP)), the crankcase ventilation system 16 draws air into the crankcase 28 through the breather or (ventilation) crankcase ventilation pipe 74. The first end 101 of the crankcase ventilation pipe 74 may be mechanically connected or connected to the fresh air inlet 12 upstream of the compressor 50. In some examples, the first end 101 of the crankcase ventilation pipe 74 may be connected to the fresh air inlet 12 downstream of the air filter 54 (as shown). In other examples, the crankcase ventilation pipe may be connected to the fresh air inlet 12 upstream of the air filter 54. In yet another example, the crankcase ventilation pipe may be connected to the air filter 54. The second end 102, opposite the first end 101 of the pipe 74 of the crankcase ventilation may be mechanically coupled or attached to the crankcase 28 of the engine through an oil separator 81.

In some embodiments, the crankcase ventilation pipe 74 may include a pressure sensor 61 connected thereto. The pressure sensor 61 may be an absolute pressure sensor or a measuring sensor. One or more additional pressure and / or flow sensors may be connected to the crankcase ventilation system at alternative locations. For example, the barometric pressure sensor 51 (BP sensor) may be connected to the inlet 56 upstream of the air filter 54 to provide an estimate of the barometric pressure (BP). In one embodiment, where the pressure sensor 61 is in the form of a measuring sensor, the BP sensor 51 may be used with the pressure sensor 61. In some embodiments, compressor inlet pressure sensor (CIP) 58 may be coupled in the intake manifold 56 downstream of the air filter 54 and upstream of the compressor 50 to provide an estimate of the compressor inlet pressure (CIP).

In naturally aspirated conditions, the crankcase ventilation system vents air from the crankcase and into the intake manifold 42 through a pipe 76, which, in some examples, may include a PCV flow valve 78 to ensure that gases are continuously evacuated from the inside of the crankcase 28 before being connected to the intake manifold 42. In one embodiment, the PCV valve may change its flow restriction in response to a pressure drop (or flow through it). However, in other examples, conduit 76 may not include a PCV flow valve. In addition to other examples, the PCV valve may be an electronically controlled valve that is controlled by the controller 48. It will be appreciated that, as used herein, the PCV stream refers to a gas stream through a pipe 76 from an engine crankcase to an intake collector. Similarly, as used in the materials of the present description, the PCV return flow refers to the gas flow through the pipe 76 from the intake manifold to the crankcase. PCV backflow can occur when the pressure in the intake manifold is higher than the pressure in the crankcase (for example, when the engine is supercharged). In some examples, the PCV system 16 may be equipped with a shutoff valve to prevent PCV backflow. It will be appreciated that while the illustrated example shows the PCV valve 78 as a passive valve, this is not meant to be limiting, and, in alternative embodiments, the PCV valve 78 may be an electronically controlled valve (e.g., a controlled valve from the powertrain control module (PCM)), while the controller can issue a command signal to change the valve position from the open position (or high flow position) to the closed position (or low flow position), or vice versa, or any position in between.

In pressurized conditions (when the MAP is larger than BP), gases flow from the crankcase through the oil separator 81 and into the fresh air inlet 12, and finally into the combustion chamber 34. This can be accomplished by the stale air method when intake manifold air is not allowed into the engine crankcase, or by the forced crankcase ventilation method when a certain amount of manifold air is dosed into the engine crankcase.

When the engine is running at low load and with moderate throttle opening, the air pressure in the intake manifold may be less than the air pressure in the crankcase. A lower intake manifold pressure draws in fresh air toward it, draws air from the crankcase ventilation pipe 74 through the crankcase (where it is diluted and mixed with combustion gases), from the crankcase through the PCV line, through the PCV valve, and into the intake manifold . However, in other conditions, such as a heavy load or in a supercharged condition, the air pressure in the intake manifold may be greater than the air pressure in the crankcase. Essentially, intake air can pass through the PCV line and into the crankcase.

The gases in the crankcase 28 of the engine may consist of unburned fuel, unburned air and fully or partially burnt gases. In addition, lubricating oil mist may also be present. As such, various oil separators may be included in the crankcase ventilation system 16 to reduce oil mist from the crankcase through the PCV system. For example, conduit 76 may include a unidirectional oil separator 80, which filters the oil from the vapors exiting the crankcase 28 of the engine before they re-enter the intake manifold 42. Another oil separator 81 may be located in the crankcase ventilation pipe 74 to remove oil from the flow of gases exiting the crankcase when working with supercharging. Additionally, in some embodiments, conduit 76 may also include a vacuum sensor 84 connected to the PCV system.

The controller 48 is shown in FIG. 1 as a microcomputer including a microprocessor unit 108, input / output ports 110, an electronic storage medium for executable programs and calibration values, shown as a read-only memory chip 112 in this particular example, random access memory 114, non-volatile memory 116 and a data bus. The controller 48 may receive various signals from various sensors connected to the engine 10, an engine coolant temperature (ECT) from a temperature sensor 46; measuring the pressure in the intake manifold (MAP) from the pressure sensor 120; barometric pressure measurement with 51 BP sensor; fuel-air ratio of exhaust gases from the exhaust gas sensor 64; and other PCV diagnostic sensors described below. The read-only storage medium 112 of the storage medium may be programmed with machine-readable data representing instructions executed by the processor 108 to perform the methods described below, as well as options that are anticipated but not specifically listed.

Under certain conditions, crankcase ventilation systems can be monitored through a variety of sensors to identify violations of the crankcase ventilation system. For example, the crankcase ventilation pipe may become disconnected, and the oil filler cap may be removed or not tightened, the oil dipstick may be removed, and / or other seals in the crankcase ventilation system may be compromised. In such a case, a deterioration in the operation of various components included in the crankcase of the engine may occur. Deterioration or disconnection of the crankcase ventilation pipe can be indicated in various ways.

In some embodiments, a plurality of absolute value sensors, such as a barometric pressure sensor (BP) 51, compressor inlet pressure sensor (CIP) 58 and / or pressure sensor 61 in the ventilation pipe 74 may be used in combination to monitor the integrity of the crankcase ventilation system . For example, in some approaches, a sensor 51, a compressor inlet barometric pressure sensor 58, and a PCV breather pipe pressure sensor 61 can all be used to monitor the integrity of the crankcase ventilation system.

In a preferred embodiment, these sensors may be possible and, in return, a humidity sensor 20 may be used to monitor the integrity of the crankcase ventilation system. The humidity sensor 20 may be located or localized within the crankcase ventilation pipe 74 closer to the first end 101. In an alternative embodiment, the humidity sensor may be located a small amount downstream from the first end 101 at the fresh air inlet 12 near the first end 101 of the ventilation pipe crankcase. The location of the humidity sensor in the crankcase ventilation pipe 74 may offer the advantage of identifying leaks in the crankcase ventilation system, such as disconnecting the crankcase ventilation pipe. For example, the read humidity of the humidity sensor 20 may be in certain ranges in a supercharged and naturally aspirated environment, and disconnecting the crankcase ventilation pipe may cause the sensor to display a different value outside these expected ranges. In this way, an indication of disconnecting the crankcase ventilation tube may be generated.

For example, when the engine is naturally aspirated, when the MAP is less than BP, the humidity sensor 20 can read environmental humidity. When operating in a naturally aspirated state, ambient air can be drawn into the crankcase through the crankcase ventilation pipe 74. In this state, the humidity sensor is exposed to ambient air. In this way, the humidity sensor senses ambient humidity. This reading can then be used by the controller to adjust the operating parameters of the engine based on the read ambient humidity. Adjusting engine operating parameters may include adjusting one or more of a radiator grill flap system, an electric fan, a variable volume charge air cooler, blowing a charge air cooler, opening a throttle to control air flow, setting the ignition timing, and downshifting operations. In yet another example, ambient humidity can be used to evaluate and / or track the formation of condensate inside the charge air cooler. Information about the formation of condensate can then be used to adjust the above operating parameters. For example, increased ambient humidity may increase condensation. In response, the controller may initiate purge operations on the charge air cooler to reduce condensation and the possibility of misfiring in the engine.

When a supercharged engine is running, when the MAP is larger than BP, the humidity sensor can sense crankcase gases and show a value greater than ambient humidity. For example, when the MAP is larger than BP, gases can exit the crankcase and enter the crankcase ventilation pipe to exit the fresh air inlet 12. These gases may have a higher humidity than ambient humidity, causing the humidity sensor to read a higher humidity value. In a crankcase ventilation system with stale air, crankcase gases may not be purged or ventilated with ambient air. If the crankcase ventilation system is designed as a stale air system in a supercharged mode, the effluent from the crankcase may become more humid, as the crankcase gases are not vented by the surrounding air. Even in crankcase systems that are continuously ventilated with fresh or ambient air, relative humidity can be high relative to ambient air. Thus, as the boost increases (for example, while the MAP> BP state continues), there may be a significant increase in humidity. After the MAP is larger than BP for a certain length of time, the humidity can be saturated at a relative humidity of substantially 100%. Thus, when the MAP is larger than the BP, the crankcase ventilation pipe can be connected if the humidity is greater than the threshold humidity. In one example, the threshold humidity may be ambient humidity plus a threshold value. The threshold value may be based on an increase in the percentage of moisture. For example, a 10% increase in relative humidity may indicate that the crankcase ventilation pipe is connected. In yet another example, this percentage may be higher than 10%. In yet another example, the threshold humidity may be a value of 100%. When humidity is essentially 100%, a crankcase ventilation pipe may be connected. In yet another example, the threshold humidity may be a value greater than ambient humidity. In yet another embodiment, if the humidity has failed to reach a threshold value, such as a relative humidity of 90%, after some time in the supercharged state, deterioration of the crankcase ventilation tube may be indicated.

Essentially, when the MAP is larger than the BP, the crankcase ventilation pipe can be disconnected if the humidity is less than the threshold humidity. For example, if the sensed humidity is less than the ambient humidity (for example, the most recent measurement of environmental humidity), the crankcase ventilation pipe may be disconnected. In another example, when the threshold humidity is greater than the ambient humidity (for example, the threshold value is a positive value) and the sensed humidity is less than this value, the crankcase ventilation pipe may be disconnected. In some cases, when switching from an operating state without pressurization to pressurization, there may be a delay in indicating a leak in the crankcase ventilation system or disconnecting the tube. This may provide a readable humidity the ability to rise by a threshold value from environmental humidity. Essentially, a false indication of disconnecting the crankcase ventilation tube may be reduced. If, after some time or delay, the humidity is not above the threshold humidity, the controller may indicate that the crankcase ventilation pipe is disconnected.

Deterioration of the crankcase ventilation system may result from deterioration of the operation or disconnection of the crankcase ventilation tube, loose or disconnected oil filler cap, improperly located dipstick and / or failure of other seals in the crankcase ventilation system, leading to deterioration of various components included in the crankcase. The crankcase ventilation pipe may become disconnected at the first end 101 or the second end 102. If the crankcase ventilation pipe 74 is disconnected at the crankcase, or the second end 102, the humidity sensor can only observe environmental humidity and not absorb wet gases from the crankcase. Thus, the humidity sensor would show a lower value than expected in a supercharged environment. Alternatively, if the crankcase ventilation pipe is disconnected at the first end 101, the humidity sensor may not detect a disconnection at the first end 101. However, if the crankcase ventilation pipe is located on the crankcase side of the engine from the humidity sensor 20, then the disconnection is detected in the same way. such as disconnecting at the second end 102. disconnecting between the PCV valve 78 and the oil separator 80, and removing the oil filler cap or improperly located dipstick can create Hb ventilation high velocity flow (dilution) of the engine at high air flow rates. Thus, the read humidity may be lower than expected due to the high proportion of ambient air diluting moist crankcase gases.

In addition to diagnosing a deterioration in the crankcase ventilation tube, a humidity sensor can provide diagnostics for the proper functioning of the humidity sensor itself. As discussed above, when the MAP is smaller than BP, the humidity sensor may indicate environmental humidity. When the MAP is larger than BP, the humidity sensor may indicate a value greater than ambient humidity. Thus, if the read humidity does not change under these two conditions, the humidity sensor may be malfunctioning. For example, if the engine’s operating mode is switched from supercharged to naturally aspirated, or from naturally aspirated to supercharged, and the sensed humidity does not change, the sensor may fail.

In conclusion, the location of the humidity sensor in the crankcase ventilation tube can also provide a measurement of gas breakthrough. When the engine is running, a small amount of fuel and exhaust gas can break between the piston 38 and the walls 36 of the chamber and enter the crankcase 28 of the engine. This may be referred to as a gas breakthrough. As engine performance deteriorates over time, gas breakthroughs may increase. Thus, a higher rate of gas breakthrough may indicate a larger amount of engine deterioration. A humidity sensor can provide an estimate of the rate of gas breakthrough. For example, when an engine goes from being naturally aspirated to supercharged, the rate of increase in humidity can approximate the rate of gas breakthrough. When the rate of gas breakthrough increases above the threshold intensity, deterioration in engine performance may be indicated. In one example, if there is excessive gas breakthrough, a humidity sensor can always show 100% relative humidity. A clogged PCV valve (for example, lack of fresh air diluting crankcase gases) can also result in a humidity sensor reading of 100% RH under both conditions, with and without supercharging. Thus, in some examples, excessive gas breakthrough and a clogged PCV valve can produce the same results with this detection method. However, both conditions may result in deterioration of the crankcase ventilation system and indicate that this is the case through this method.

Thus, an indication of the disconnection of the crankcase ventilation pipe may be based on humidity detected by a humidity sensor located in the crankcase ventilation pipe. When the MAP is smaller than BP, the humidity sensor can indicate ambient humidity. The controller, in this case, can adjust the operating parameters of the engine based on the read humidity of the environment. When the MAP is greater than BP, the humidity may be greater than the threshold humidity, indicating that the crankcase ventilation pipe is disconnected. However, when the read humidity is less than the threshold humidity, the crankcase ventilation pipe may be disconnected. The humidity sensor can additionally provide diagnostics of the functioning of the humidity sensor and evaluate the rate of gas breakthrough.

In an alternative embodiment, MAP and compressor inlet pressure (CIP) and / or MAP and crankcase pressure can be used instead of MAP and BP to determine when the engine is boosted or boosted. Thus, the relationship between MAP and CIP or crankcase pressure can be used to evaluate the readings from the humidity sensor and determine the deterioration of the crankcase ventilation pipe. For example, when the MAP is smaller than the CIP, the engine may not be boosted and the humidity sensor may indicate ambient humidity. In yet another example, when the MAP is greater than CIP or crankcase pressure, the humidity may be greater than the threshold humidity, indicating that the crankcase ventilation pipe is connected or not subject to performance degradation. Thus, in the present description, CIP and / or crankcase pressure can be used instead of BP in determining the working conditions of a supercharged / non-supercharged engine and analyzing the readings of a humidity sensor.

Referring to FIG. 2, a method for diagnosing a crankcase ventilation pipe connection is shown. The procedure begins at step 202, in which the engine operating conditions are evaluated and / or measured. Engine operating conditions may include engine speed and engine load, MAP, humidity (for example, sensed humidity measured from humidity sensor 20), air mass flow, barometric pressure (BP), etc. At step 204, the controller can use this information to determine if the engine is boosted. For example, if the MAP is larger than BP, the engine may be boosted; otherwise, it may be determined that the engine is not boosted. A method for determining engine boost is presented in more detail in FIG. 3. If the engine is not boosted in step 204, the humidity sensor can read the ambient humidity. Thus, in step 206, the ambient humidity value is set to the read humidity value from the humidity sensor. At step 208, a diagnosis is made of the lack of connection of the crankcase ventilation pipe. The method proceeds to step 210 to adjust the operating parameters of the engine based on the read ambient humidity. Adjusting engine operating parameters may include adjusting one or more of a radiator grill flap system, an electric fan, a variable volume charge air cooler, blowing a charge air cooler, opening a throttle to control air flow, setting the ignition timing, and downshifting operations. For example, in response to increased ambient humidity, the controller may close the radiator grille shutters to reduce cooling in relation to and form condensation in the CAC. Thus, engine operating parameters can be adjusted in response to ambient humidity. When the engine is not pressurized and the humidity sensor senses ambient humidity, engine performance parameters, such as the radiator grille system, can be adjusted in response to the sensed humidity. However, when the engine is boosted, the read humidity may not indicate ambient humidity. Thus, in this case, the operating parameters of the engine can be adjusted based on the latest humidity sensor reading (for example, in naturally aspirated conditions). For example, radiator grill shutters may open or close based on the most recent estimate of ambient humidity based on read humidity when the engine was not pressurized. Essentially, engine operating parameters can be continuously adjusted under engine conditions, both naturally aspirated and supercharged.

Returning to step 204, if the engine is boosted, the procedure proceeds to step 212 to determine if the read humidity is greater than the threshold humidity. The threshold humidity may be ambient humidity plus a threshold value. In one example, the threshold value may be small so that the threshold humidity is a value just above ambient humidity. In yet another example, the threshold value may be greater so that the threshold humidity has a value of about 100%. The threshold value may be based on a previous environmental humidity value and engine operating conditions. For example, an increase in relative humidity at a threshold value during boost may indicate that the crankcase ventilation pipe is not degrading, or that the crankcase ventilation pipe is connected. In one example, the threshold value may be an increase in percent, such as 10%. In another example, the percentage increase may be higher. In some embodiments, a humidity (e.g., relative humidity) substantially 100% may indicate that the crankcase ventilation pipe is connected.

If the sensed humidity is greater than the threshold humidity, in step 212, the procedure determines, in step 214, that the crankcase ventilation pipe is connected. However, if the read humidity is not greater than the threshold humidity, in step 212, the procedure determines, in step 216, that the crankcase ventilation pipe is disconnected. In some examples, the procedure in step 216 includes the step of indicating to the driver or driver of the vehicle that the crankcase ventilation pipe is disconnected. In some embodiments, the method 200 may include an additional step after 212, which waits a certain length of time, and then re-checks whether the read humidity is still below the threshold humidity, at step 212. This may provide time, so that the humidity sensor is balanced and comes to a steady value. For example, when switching from a naturally aspirated state to a supercharged one, it may take some time for the humidity to rise above a threshold value. In this case, the crankcase ventilation tube can be connected if the sensed humidity is greater than the threshold humidity after a certain length of time. This time duration or delay may be small if the threshold humidity is only a small amount higher than the ambient humidity in step 212.

A method for determining engine boost and gas breakthrough intensity is shown in FIG. 3. Method 300 begins at block 302, in which the MAP and read moisture values are determined. At step 304, the procedure determines whether the MAP is smaller than the BP. If the MAP is not less than BP, the procedure determines that the MAP is greater than or substantially equal to BP in step 306. Essentially, the procedure determines that the engine is boosted in step 310. This condition is then used, as discussed above, in the method figure 2.

Returning to step 304, if the MAP is less than BP, the procedure determines at step 312 that the engine is not boosted. The routine proceeds to step 314, which confirms whether the MAP is incremental. If the MAP does not increase, the procedure determines that the MAP is in steady state, at step 316, and then ends. However, if the MAP increases at step 314, the procedure continues to check if the MAP is larger than the BP at step 318. In some examples, the procedure at step 318 may include a step in which some time is expected before checking the value again MAP relative to BP. If the MAP is not larger than BP in step 318, the procedure continues to monitor the increase in MAP in step 320, and returns to step 314. If the MAP is larger than BP in step 318, the procedure then monitors the rate of increase in humidity by the sensor humidity (for example, read humidity) in step 322. In step 324, the procedure determines whether the read humidity is in steady state (for example, no longer rising). If the humidity is not in steady state (for example, it is still rising), the procedure continues to measure the rate of increase in the read humidity, at step 326, and then returns to step 324.

Once the procedure determines, at step 324, that the read humidity has reached a steady state, the procedure then determines the rate of gas breakthrough at step 328. The rate of gas breakthrough can be based on the rate of increase in read humidity. For example, a higher rate of increase in humidity may indicate a higher rate of gas breakthrough. Essentially, the rate of increase in humidity can approximate the rate of gas breakthrough. At 330, the procedure can determine if the estimated rate of gas breakthrough is greater than the threshold intensity. If the rate of gas breakthrough is greater than the threshold intensity, engine deterioration may be indicated at 334. In some embodiments, an indication may be generated to alert the driver of the vehicle of engine deterioration. If the gas breakthrough intensity is not greater than the threshold intensity, engine performance deterioration may not be indicated at step 332. The gas breakthrough threshold intensity may be based on an acceptable gas breakthrough rate for the vehicle. For example, the threshold intensity can be determined so that the amount of gas breakthrough below this threshold value could be due to the normal operation of the vehicle, and not an increased deterioration in the operation of engine components.

Next, with reference to FIG. 4, graph 400 shows exemplary humidity sensor readings based on engine operating conditions. More specifically, graph 400 shows changes in MAP relative to BP in graph 402 and changes in read humidity (from humidity sensor 20) in graph 404. In response to MAP and read humidity, an indication of the connection (C) or disconnection (D) of the crankcase ventilation pipe (CV) ) from the crankcase ventilation system can be shown in graph 406. When the MAP is larger than BP, the engine is boosted, and when the MAP is smaller than BP, the engine is not boosted. Environmental humidity 408 is shown in graph 404 and changes based on read humidity when the MAP is less than BP. The sensed humidity (for example, humidity removed from the humidity sensor 20) can rise to 100% when the engine is boosted.

Until time t1, the MAP may be lower than BP (e.g., naturally aspirated engine) (plot 402). As a result, the read humidity is ambient humidity 408 (plot 404). Until time t1, diagnostics for connecting the crankcase ventilation pipe is not performed. At time t1, the MAP rises above BP, changing engine operation from naturally aspirated to supercharged (graph 402). As a result, the read humidity rises from time t1 to time t2 (plot 404). The read humidity can rise above the threshold humidity 410 after a length of time d1. In response, the controller may generate an indication that the crankcase ventilation pipe is connected (graph 406). As described in method 200, there may be a delay in indicating that the crankcase ventilation pipe is disconnected when the engine is switched from being supercharged to supercharged. This delay allows the sensed humidity to rise above the threshold humidity and reduce the likelihood of a false indication of disconnection of the ventilation tube. In the example shown in graph 400, a delay may occur for a length of time d1. The threshold humidity 410 may be a threshold value T1 above the level of environmental humidity. In yet another example, the threshold value T1 may be smaller or larger. If the threshold value T1 was less, the length of time d1 may be shorter, allowing the diagnostic delay to be shorter.

From time t1 to time t2, the controller can control the rate of increase in humidity R1. This moisture increase rate R1 can then be used to approximate the rate of gas breakthrough. In the example shown in graph 400, the rate of increase in humidity R1 can be quite low so that the rate of gas breakthrough is lower than the threshold intensity. Thus, engine degradation may not be indicated.

At time t2, the sensed humidity saturates at 100% humidity (plot 404), indicating that the crankcase ventilation pipe remains attached. At time t3, the MAP decreases below BP (plot 402), causing the read humidity to drop and show ambient humidity 408 (plot 404). After time t3, the diagnosis of the crankcase ventilation pipe may not be performed. Between time t3 and time t4, the sensed humidity may slightly increase (graph 404), indicating an increase in ambient humidity 408. At time t4, the engine switches to boost operation and the MAP rises above BP (graph 402). The read humidity rises with a high rate of increase in humidity R2. As a result, the read humidity quickly reaches a threshold humidity of 410, requiring only a short delay in the diagnosis of the crankcase ventilation tube. As soon as the sensed humidity rises above the threshold humidity 410, the controller may indicate that the crankcase ventilation pipe is connected. Since the rate of increase in humidity R2 may be higher, the rate of breakthrough of gases can be estimated at a value above the threshold intensity. Thus, deterioration in engine performance can sometimes be indicated between time t4 and time t5.

At time t5, the read humidity can be saturated up to 100% and remains there until time t6 (graph 404). At time t6, the sensed humidity can sharply decrease to a level below threshold humidity 410. At this point in time, the MAP remains above BP. This may indicate disconnection of the crankcase ventilation pipe (graph 406). In response, the controller may generate an indication to disconnect the crankcase ventilation pipe or a leak in the crankcase ventilation system.

Thus, a humidity sensor located in the crankcase ventilation tube can give an indication of environmental humidity. Engine performance can be adjusted based on this humidity. In addition, the deterioration of the crankcase ventilation tube may be based on read moisture and engine boost. For example, as shown at time t6, the crankcase ventilation pipe may be disconnected when the engine is pressurized and the sensed humidity is ambient humidity. In another example, as shown between time t1 and time t3, and between time t4 and time t6, the crankcase ventilation pipe may be connected when the engine is pressurized and the sensed humidity is at a threshold value above ambient humidity. The read humidity may be ambient humidity when the engine is not pressurized, as shown before time t1 and between time t3 and time t4. In yet another example, during the transition state, when the engine changes from being without boost to staying with boost (as shown at time t1 and time t4), the rate of increase in humidity approximates the rate of gas breakthrough. As shown at time t4, a higher rate of increase in humidity and, correspondingly, a higher rate of breakthrough of gases, indicates a large amount of deterioration in engine operation.

Thus, by positioning the humidity sensor in the crankcase ventilation pipe, diagnostics of the crankcase ventilation pipe connection can be diagnosed. In one example, when the engine is pressurized and the sensed humidity is a threshold value higher than ambient humidity, a crankcase ventilation pipe may be connected. In yet another example, when the engine is boosted and the sensed humidity is less than the threshold humidity, the crankcase ventilation pipe may be disconnected. When the engine is not boosted, the sensed humidity can indicate ambient humidity. In response to this environmental humidity, the controller can adjust the operating parameters of the engine. The location of the humidity sensor in the crankcase ventilation tube may additionally provide an opportunity to estimate the rate of gas breakthrough based on the rate of increase in humidity when the engine is switched from naturally aspirated to supercharged. Higher gas breakthrough rates may indicate deterioration in engine performance. In conclusion, the proper functioning of the humidity sensor can be determined by monitoring changes in the read humidity under different engine operating conditions. Thus, the location of the humidity sensor in the crankcase ventilation pipe may provide an opportunity for diagnosing the crankcase ventilation pipe, in addition to diagnosing the functionality of the humidity sensor and impairing engine performance.

Note that the exemplary control procedures included in the materials of the present description can be used with various configurations of the engine and / or vehicle systems. The specific procedures described herein may be one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, the various acts, operations or functions illustrated can be performed in the illustrated sequence, in parallel, or in some cases skipped. Similarly, a processing order is not necessarily required to achieve the features and advantages of the exemplary embodiments described herein, but is provided to facilitate illustration and description. One or more of the illustrated actions or functions may be performed repeatedly, depending on the particular strategy used. In addition, the described actions can graphically represent code that must be programmed on a computer-readable storage medium in an engine control system.

It will be appreciated that the configurations and procedures disclosed herein are exemplary in nature, and that these specific embodiments should not be construed in a limiting sense, as numerous variations are possible. For example, the above technology can be applied to engine types V6, I-4, I-6, V-12, opposed 4-cylinder and other engine types. In addition, one or more different system configurations may be used in combination with one or more of the described diagnostic procedures. The subject of this disclosure includes all the latest and non-obvious combinations and subcombinations of various systems and configurations, and other features, functions and / or properties disclosed in the materials of the present description.

Claims (1)

A system for an engine comprising: a forced crankcase ventilation system comprising a crankcase ventilation pipe, wherein the crankcase ventilation pipe is connected at the first end to the fresh air inlet and at the second end to the engine crankcase; humidity sensor located inside the crankcase ventilation tube; manifold absolute pressure sensor; and a controller with machine-readable commands for adjusting engine operating parameters based on humidity read by a humidity sensor, and indicating deterioration of the crankcase ventilation tube based on humidity read by a humidity sensor and engine boost.

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